<html>
<head>
<style type="text/css" media="screen">
  body { background:green; }
</style>
<script>
var styleElements = [];
function handleMessage(event)
{
    function addStyleSheet(styleContent)
    {
        var styleElement = document.createElement("style");
        styleElement.textContent = styleContent;
        document.head.appendChild(styleElement);
        styleElements.push(styleElement);
    }

    switch (event.data) {
    case "addStyleSheets":
        addStyleSheet("body { background-color: yellow; }");
        addStyleSheet("body { background-color: yellow; }\n/*# sourceURL=stylesheet-added-in-iframe.css */");
        break;
    case "removeStyleSheets":
        for (var i = 0; i < styleElements.length; ++i)
            document.head.removeChild(styleElements[i]);
        styleElements = [];
        break;
    }
}

window.addEventListener("message", handleMessage, false);
</script>
</head>

<body>
</body>

</html>
